The present invention relates to the field of photography and, more particularly, to an ambient light excluding folding bellows for use in folding cameras of the type including a mirror in the exposure optical path.
Integral self-developing film units of the general type disclosed in commonly-assigned U.S. Pat. Nos. 3,415,644; 3,594,165 and 3,761,268 and marketed by Polaroid Corporation, Cambridge, Mass., under the tradenames SX-70, TimeZero and 600 High Speed Land Film are exposed and viewed through the same side of the film unit thereby requiring an odd number of image reversals in the exposure optical path for correct image orientation.
Most commonly, cameras designed for this type of film include a horizontal base section for supporting a film pack with the forwardmost film unit therein located at the camera's film or exposure plane; an upstanding lens and shutter housing located at the forward end of the base section and supporting the lens with its optical axis generally parallel, or at some other non-peripheral angle, to the film plane; and a mirror mounted at the opposite end of the base section with its forwardly directed reflective surface inclined at an appropriate angle with respect to the film plane and lens axis to reflect image forming light from the lens down onto the film unit for exposure. The mirror thus provides the necessary additional image reversal and also allows the relatively long optical path required for focusing an image on a snapshot sized film unit to be folded thereby making the camera more compact in its exposure configuration.
The present invention is directed to a folding bellows for use in folding cameras of this type which include a housing comprising a plurality of sections that are interconnected for relative movement between an erected exposure position and a folded storage position.
Such folding cameras are well-known in the prior art. For representative examples, see U.S. Pat. Nos. 3,479,941; 3,589,253; 3,683,770; 3,722,389; 3,877,046 and 4,166,683.
Typically, these cameras include a base housing section, a lens and shutter housing pivotally coupled to the forward end of the base section, a long cover section coupled to the trailing end of the base section and a short cover section pivotally coupled to the upper end of the lens and shutter housing and the forward end of the long cover section. So arranged, these four housing sections comprise a four-bar linkage adapted to be moved between a flat folded configuration and an erected exposure position. When erected, the upright lens and shutter housing, short cover and long cover form a longitudinally extending tent-like structure over the base section to locate the lens and mirror in optical relation to one another and a film unit at the exposure position. The open lateral sides of the structure are enclosed by an erected light opaque bellows.
As the camera is folded, the lens and shutter housing pivots forwardly and downwardly in front of the forward end of the base housing section to assume its storage position in substantially coplanar end-to-end relation therewith and the short and long cover sections are aligned in planar end-to-end relation overlying the lens and shutter housing and the base section respectively. The bellows is attached to various housing sections and automatically folds therewith into a longitudinally extended flat shape for storage between the overlying housing sections.
The mirror generally is mounted on the interior surface of the long cover section, within the confines of the bellow, for movement therewith between its erected exposure position and a flat storage position overlying and facing the film plane.
Other cameras of this general type do not employ the four bar linkage folding scheme. For examle, see an alternative embodiment shown in FIG. 8 of the previously-noted U.S. Pat. No. 3,683,770 wherein the camera comprises two pivotally coupled major housing sections which are arranged in overlying relation when the camera is folded and pivot open to a preset angle to erect a bellows that cooperates with the major housing sections to form a generally triangular camera structure. One housing section serves as the receiving chamber for the film pack and the other supports the lens and mirror thereon.
U.S. Pat. No. 3,836,933 discloses a folding self-developing camera for use with film that does not requires an additional reversal for correct image orientation, but does employ two mirrors providing an even number of reversals to fold the exposure optical path in the interest of structural compactness of the erected camera. The mirrors are attached to a foldable frame within a bellows which is also attached to the frame to facilitate folding the bellows.
A common characteristic of all of the above-noted prior art cameras is that the exposure mirror, the portion of the bellows adjacent the mirror, and the mirror support structure have fixed relative positions to facilitate folding or erecting the camera. However, this limits the number of different ways in which the various housing sections may be arranged in the folded position. In other words, the inability to move the mirror, bellows and/or mirror support structure independently of or relative to one another during the folding and erection sequence severely limits the number of possible options for arranging the various housing sections in the folded position.
It is obvious that the folding action of the bellows (its movement between erected and storage positions) must be integrated into the folding scheme of the camera so as not to interfere with the motion of other camera components.
The present invention is directed to a folding bellows that is configured to be compatible with a folding camera that also has a mirror in its exposure optical path but utilizes a different folding scheme than the camera's described above in that the lens housing is pivotally mounted so as to be folded back over the base section in overlying relation to the film plane.
Therefore, it is an object of the present invention to provide a folding bellows that is configured to move between erected and storage positions in a manner that is compatible with the movements of other components of such a camera.
It is another object to provide such a bellows that is simply constructed and folds into a substantially flat storage configuration to minimize the dimensions of the folded camera.
Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.